The aeronautical sector must consider whether to adapt traditional engines or have electric propulsion systems with fuel cells; use liquid or gaseous hydrogen, and even its “color”
According to the IDTechEx report, “Sustainable Aviation 2025-2045: Trends, Technologies, Forecasts,” hydrogen fuel will likely be a key competitor in decarbonizing the aviation industry, as its usage will exceed $20 billion ( million) in 2045.
However, James Jeffs, Principal Technology Analyst at IDTechEx, explained that before the industry can celebrate a significant reduction in carbon emissions, he said it is crucial to carefully consider the technology used in aircraft and the source of the hydrogen.
“If not implemented correctly, hydrogen-powered aircraft could be more harmful to the environment than current fossil fuel-powered aircraft,” he said.
The manager explained that companies in the aeronautical sector must consider three fundamental aspects for the development and operation of commercial aircraft powered by hydrogen: deciding whether they should use traditional jet engines adapted to run on hydrogen or electric propulsion systems with fuel cells; whether they should use cryogenic liquid hydrogen or pressurized gaseous hydrogen, and even the “color” of the hydrogen.
Jeffs stated that these decisions will affect the carbon footprint, the range of the aircraft and their ability to replace routes currently operated with fossil fuel. “Making the wrong decisions at every stage could result in hydrogen aircraft becoming a mere greenwashing strategy.”
*Hydrogen internal combustion vs fuel cells*
Hydrogen internal combustion engines (H2ICE) will likely appeal to engine suppliers such as Pratt & Whitney, General Electric and Rolls-Royce, as their designs closely resemble current turbine engines.
However, these engines will not be as efficient as fuel cell-based electric powertrains, which offer 50% more range with the same amount of hydrogen and a 33% smaller carbon footprint if a fuel source is used. non-carbon neutral hydrogen.
*Liquid hydrogen vs pressurized hydrogen*
The main challenge of hydrogen is its low volumetric energy density. Although it is lighter than conventional fuel, it takes up much more space, which means it needs to be compressed or liquefied.
Liquid hydrogen is the option that offers the best autonomy, but requires keeping it at extremely low temperatures, which would complicate its storage and handling both in airports and on airplanes.
*The “color” of hydrogen*
Most of today’s hydrogen comes from gray and black sources, which emit large amounts of CO2 during their production. Viable options to reduce emissions are green hydrogen, produced by electrolysis of water with renewable energy, and blue, which captures carbon emissions during its production.
However, both are significantly more expensive than gray and black hydrogen, posing a challenge for airlines that could face increases in costs or ticket prices.
“While hydrogen represents a realistic path toward decarbonizing aviation, its implementation comes with significant challenges. Aeronautical companies, engine manufacturers and airlines will need to make complex decisions about propulsion technology, hydrogen storage status and its source,” Jeffs concluded.
